Storm Daniel turns deadly as it ravages Greece, Turkey with flooding rain

Storm Daniel, a massive storm churning over the southeastern Mediterranean, has turned deadly as it continues to unleash historic and flooding rainfall. And its impacts are not over yet, AccuWeather forecasters say.

At least 14 people have been killed by the storm, according to the Associated Press, with fatalities reported by officials in Bulgaria, Greece and Turkey.

Intense rainfall is expected to drench the southeast corner of the Mediterranean Sea through late this week as Daniel circulates to the southwest of Greece. Due to the nature of the heavy rainfall in Greece, red warnings were issued by the Hellenic National Meteorological Service, the Greek government weather agency, warning of "particularly intense" weather with heavy rain and storms across the region.

In the government's three-tier warning system, red warnings are the highest category of warning that can be issued for the country, specifically used for dangerous and severe weather phenomena.

The storm comes just days after a separate storm caused extreme flooding on the other end of the Mediterranean, across parts of Spain and Portugal, over the weekend.

"Heavy rain will continue in Greece through Thursday thanks to an Omega block keeping Storm Daniel nearby for a couple of additional days," explained AccuWeather Senior Meteorologist Jason Nicholls.

Damaged cars are pilled up in the mud after a record rainfall in Milina village, Pilion region, central Greece, Wednesday, Sept. 6, 2023. Rescue teams in Turkey, Greece and Bulgaria have recovered more bodies following floods after fierce rainstorms. (AP Photo/Thodoris Nikolaou)

Damaged cars are pilled up in the mud after a record rainfall in Milina village, Pilion region, central Greece, Wednesday, Sept. 6, 2023. Rescue teams in Turkey, Greece and Bulgaria have recovered more bodies following floods after fierce rainstorms. (AP Photo/Thodoris Nikolaou)

AccuWeather experts define an "Omega block" as a buckling pattern in the jet stream, which resembles the Greek letter "Omega," hence the name. This setup tends to prevent the normal west-to-east movement of weather features and tends to lock in cooler, stormy conditions in some spots.

On Monday, a report from the European Severe Weather Database indicated that a waterspout swirled off the coast of Mantoúdi, a village located in the Euboea region of east-central Greece, as a result of the energy swirling from Daniel. Another funnel cloud was observed along the coast of the Tyrrhenian Sea in Bagnara Calabra, located in southern Italy. Forecasters warn that additional waterspouts can occur along the coastlines over the upcoming days, particularly along the southern coasts.

Not everyone heeded the warnings. Volos Mayor Achilles Beos was so frustrated that he took to the streets, shouting at drivers. According to Storyful, Beos stood in the floodwaters shouting, "Where are they going? It's crazy what's happening; we've said it a hundred times. We have been telling you since yesterday the rivers will break... go to your homes!"

On Tuesday, police departments ordered traffic bans for the hardest hit locations of Volos, Pelion and the island of Skiathos, all located in east-central Greece. Given the additional rainfall expected across the country, further traffic bans may be issued until the historic storm subsides.

Also on Tuesday, the Greek village of Portaria reported 23.65 inches (600.6 mm) of rainfall since the start of the day, with rain still ongoing across the area. Other nearby locations across the Volos and Agia provinces along the east-central coast of Greece recorded amounts of 7.64 inches (194 mm).

Over 222,000 lightning strikes were detected over Greece, Turkey, the Black Sea, Bulgaria, North Macedonia, Albania, and the Mediterranean Sea in the two days prior to Tuesday evening local time.

Over 222,000 lightning strikes were detected over Greece, Turkey, the Black Sea, Bulgaria, North Macedonia, Albania, and the Mediterranean Sea in the two days prior to Tuesday evening local time.

By Thursday morning, floodwaters in some areas of western Greece had reached the roofs of homes, leading to a dangerous emergency for stranded residents.

According to the AP, a flash flood in northwestern Turkey near the Bulgarian border killed five people, and at least another person was still missing.

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The ZEUS Long-Range Lightning Detection System operated by the National Observatory of Athens registered over 30,000 lightning strikes across Greece by the evening hours on Tuesday, local time, with potent thunderstorms still rumbling over the area. From Sunday afternoon to Tuesday evening, over 220,000 lightning events were recorded across the region by AccuWeather Lightning Strike data.

A visible satellite image shows the storm rotating over the Mediterranean Sea Tuesday evening local time.

A visible satellite image shows the storm rotating over the Mediterranean Sea Tuesday evening local time.

Impacts of significant flooding, bridge failures, overflowing riverbanks and mudslides have occurred in locations of Bulgaria, North Macedonia, and southern Albania earlier this week. Fortunately, by Thursday, rain and wind from Daniel had diminished across these Balkan countries.

Outer bands of rain stretching from Daniel even reached parts of southern Italy, and rainfall is expected to persist in these locations through the end of the week as the storm slowly shifts southward across the Mediterranean.

Rain totals in southern Italy have not been as extreme as in Greece, but amounts of 1.15 inches (29.2 mm) have been observed across the higher terrain of Sila National Park.

NASA's Global Precipitation Measurement product shows over 18 inches of rain in parts of Greece. (NASA)

NASA's Global Precipitation Measurement product shows over 18 inches of rain in parts of Greece. (NASA)

In the western Mediterranean last weekend, a separate storm spread severe thunderstorms and widespread heavy rain across parts of Spain and Portugal. The cyclone was named Storm Dana by the Spanish Meteorological Agency over the weekend.

Numerous reports of flooding, damaging wind gusts, hail and tornadoes occurred as the storm circulated over the Iberian Peninsula. The flooding was so severe that a 10-year-old boy needed to be rescued after clinging to a tree overnight in order to escape the torrential floodwaters.

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